Firing mechanism



1951 A. J. GRANDY 2,996,989

FIRING MECHANISM Filed March 4, 1960 IN VEN TOR. Iii-9i ANDREW J. GRANDY BY 3.}. Fatwa a J. QWMVJW ATTORNEYS! Patented Aug. 22, 1961 2,996,989 FIRING MECHANISM Andrew J. Grandy, North Hills, Pa., assignor to the United States of America as represented by the Seeretary of the Army Filed Mar. 4, 1960, Ser. No. 12,879

1 Claim. (Cl. 102-70) (Granted under Title '35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to mechanisms for firing explosive components, and more particularly to an improved firing mechanism which is simple in structure, is light in weight, is always ready for use in a safe condition, and is incapable of being accidentally actuated.

As will appear, these and other desirable objects are achieved by the provision of a firing pin and a scar which are movable together in a bearing and separate from one another when the sear is moved out of the bearing. While in the bearing the sear and firing pin are interlocked and a spring functions to maintain them in a position such that the striker of the firing pin is slightly spaced from the explosive component. When the sear is pulled out of the bearing, the spring is compressed, the sear separates from the firing pin, and the spring drives the striker against the explosive component.

The invention will be better understood from the following description when considered in connection with the accompanying drawings and its scope is indicated by the appended claims:

Referring to the drawings:

FIG. 1 illustrates the firing mechanism in its standby condition,

FIG. 2 shows the firing mechanism in the act of firing,

FIG. 3 shows the firing mechanism in its fired condition, and

FIG. 4 shows the firing mechanism as utilized to fire a recoilless gun.

As indicated by FIGS. 1 to 3, the firing mechanism of the present invention includes a tubular member which is reduced in diameter for some distance from one end to provide a bearing 11 with an internal shoulder 12 at its inner end. A closure 13 is fixed to the other end of the tubular member and is formed to provide a seat for an explosive component which is shown as a primer 14. i

A firing pin 15 and a sear 16 have interlocking surfaces 17 and 18 which engage one another when the sear and firing pin are in the position illustrated by FIG. 1. The firing pin 15 has an external flange 19 adjacent its striker 20. The sear 16 has an external flange 21. Between the shoulder 12 and the flange 19 is a spring 22 which is slightly compressed for holding the various parts in the position indicated by (FIG. 1. In this position, the striker is spaced from the primer 14.

The operation of the mechanism is started by withdrawing a safety pin 23 which interlocks the sear and firing pin with tubular member 10. This permits the sear and safety pin to move in the bearing 11 in response to a pull upon the lanyard 24.- When the sear 16 has moved to the position shown in FIG. 2, the cam surfaces 17 and 18 slip apart, releasing the spring 22 and firing the primer 14. To insure complete safety to the operator, and as clearly indicated in FIG. 2 of the drawings, the spring 22 and external flange 19 of firing pin 15 are in their most forward position immediately prior to firing as will also be the case immediately after firing when primer blowback forces urge the spring and firinf pin to its illustrated position. It is apparent then that these dangerous blow-back products cannot escape either through the holes provided in the tubular member 10 evacuated by the safety pin 23 or past the firing pin external flange.

The above described mechanism may be utilized to fire pyrotechnic devices, mortars, land mines, demolition charges and various other devices. It is shown in FIG. 4 as utilized to fire a round 25 from a launcher 26. To this end, the primer 14- is arranged to fire an igniter cord 27. This cord functions upon its firing in a well known manner to fire the primer 28 of the charge 25.

In addition to the advantages previously mentioned, the mechanism of the present invention is capable of in line firing or remote operation, maintains the spring in a relaxed state during storage, and is so constructed as to be readily substituted for a previously used mechanism.

I claim:

The combination of an explosive component and a mechanism for firing said component, said mechanism comprising a tubular member having a rear open end and a front open end, said tubular member including a wall portion extending from said front open end a short distance rearwardly of greater thickness than the remaining wall thickness of the tubular member to provide a bearing of reduced diameter, said thicker walled portion forming an internal shoulder at its inner end with the thinner walled portion of said tubular member, a closure fixed about the rear open end of said tubular member and formed to provide a seat for said explosive component, a firing pin and a sear having interlocking surfaces, said firing pin and said sear being axially movable through said bearing and said tubular member front open end in interlocked relation and separable upon the withdrawal of said seat from said bearing, a striker at the rearmost portion of said firing pin and spaced from said explosive component, a first flange integral the firing pin and forwardly adjacent the striker, a spring surrounding said firing pin and extending between said first flange and said shoulder, a second flange integral the sear forwardly the tubular member in contact relation therewith, said second flange being maintained against the forward end of said tubular member by said spring, said tubular member and sear and firing pin being provided with a communicating transverse hole therethrough, a removable safety pin received through said hole for interlocking said sear and said firing pin to said tubular member, said hole being disposed in the tubular member forwardly of said spring and through the thicker walled portion forming said bearing.

References Cited in the file of this patent UNITED STATES PATENTS 1,675,118 Lucas June 26, 1928 1,512,249 Sprague r Oct. 21, 1944 2,382,872 Giles Aug. 14, 1945 FOREIGN PATENTS 866,767 France June 9, 1941 

